The hand of time rested on the half-hour mark, and all along that old front line of the English there came a whistling and a crying. The men of the first wave climbed up the parapets, in tumult, darkness, and the presence of death, and having done with all pleasant things, advanced across No Man's Land to begin the Battle of the Somme. - Poet John Masefield.

Membranes have been used to de-gassify water for years now, but they are only small scale units suitable for laboratory experiments. Some industrial processes have to 'dearate' water to work properly. I believe this later process is achieved by (almost) filling a tank then pumping out the remaining air. The reduction in pressure causes the gas bubbles to expand and rise to the surface